What type of mosquitoes do Gambusia affinis primarily feed on?

Gambusia affinis, commonly known as the mosquitofish, primarily feeds on the larvae of mosquitoes. This feeding behavior makes them an important biological control agent in managing mosquito populations. As they consume mosquito larvae, they help reduce the number of adult mosquitoes that can emerge, which is crucial in mosquito control efforts.

In contrast, the other options, such as adults, eggs, and even the slightly distinct larvae forms, do not provide the same level of impact on the overall mosquito population as the larvae do. Adult mosquitoes are usually not targeted as food by Gambusia affinis, as their diet is focused on the aquatic life stages of mosquitoes. Similarly, while they may interact with mosquito eggs, they do not actively target them as part of their diet. Therefore, the correct answer emphasizes the specific role that Gambusia affinis plays in controlling mosquito populations through its consumption of larvae.